A positioning technology is a technology used to determine a geographical location of a mobile station (also called a user equipment or UE). Location information of the mobile station can be directly or indirectly obtained by using resources of a wireless communications network. Generally, there are the following positioning manners:
1. Network-assisted global navigation satellite system (GNSS) positioning
2. Downlink positioning (in a manner of an observed time difference of arrival (OTDOA))
3. Enhanced cell identity (enhanced Cell ID, e-CID) positioning
4. Radio frequency pattern matching (RFPM) positioning
Generally, an algorithm for positioning a mobile station in a Long Term Evolution (Long term evolution, LTE) mobile communications system can detect characteristic parameters (such as signal field strength, a time difference of arrival of propagated signals, and an angle of arrival of a signal) of a radio wave propagation signal transmitted between the mobile station and a base station, and then a geometric location of a mobile terminal is estimated according to a relevant positioning algorithm. In a positioning method of the GNSS, the mobile station is required to have a wireless receiver for receiving a GNSS signal, and specific implementation of the GNSS includes GPS positioning, Galileo positioning, and the like. Both the downlink positioning and the e-CID positioning are a type of network positioning and a current research focus. They mainly rely on detection of characteristic parameters of wireless resources in a mobile communications system, and then estimate a location of a mobile station according to a positioning algorithm. In OTDOA positioning, downlink positioning reference signals from multiple base stations are received and measured periodically by using a mobile station, a time difference of arrival of positioning reference signals (positioning reference signal, PRS) between the base stations is reported, and calculation is performed on a network control device to obtain a geographical location of the mobile station. RFPM positioning is to compare a parameter that is measured in advance and stored in a database with a parameter that is reported during user measurement, so as to obtain a corresponding coordinate, where the coordinate indicates a location of a mobile station.
For a requirement of positioning precision, the Federal Communications Commission (FCC) of the United States of America released the E-911 regulation in 1996, requesting that wireless cellular systems of various telecommunication operators in the United States of America should be able to provide, before Oct. 1, 2001, a positioning service with precision within 125 m for a mobile station initiating an E-911 emergency call, and a probability of meeting this positioning precision should be no lower than 67%. In 1998, the FCC again put forward a service requirement, with positioning precision of 400 m and accuracy no lower than 90%. In 1999, the FCC put forward a new requirement for the positioning precision: for network-based positioning, 67% of the positioning precision should be within 100 m, and 95% of the positioning precision should be within 300 m; and for mobile-station-based positioning, 67% of the positioning precision should be within 50 m, and 95% of the positioning precision should be within 150 m.
Currently, with continuous development of mobile communications technologies, requirements for the positioning service are ever increasing. Application scenarios of the positioning service tend to be diversified, such as positioning for emergency rescue, tracking of a position of crime, navigation, and transportation control. A positioning requirement in the industry is always a hope for obtaining a reliable, effective, and fast method, no matter how diversified the application scenarios are. In other words, a positioning technology easy to implement with high precision is always in hot pursuit of people. Currently, a user equipment is generally capable of bearing services of multiple wireless networks, such as 2G/3G/LTE, and a wireless network also tends to have a vertical layout. However, UE positioning solutions provided in the prior art are applicable to a wireless network environment that involves only one standard, but are not applicable to an environment with multiple wireless networks.